A clamping cylinder with a semi-circular brake connection

Abstract

A locking cylinder with a semi-ring brake type connection includes a tie rod, a locking cylinder barrel, a locking cylinder rear cover, a piston, two semi-ring nuts, and an anti-loosening gland; the rear cover is fixed to the rear of the locking cylinder barrel to form the cylinder body of the locking cylinder; the piston is placed in the inner cavity of the locking cylinder barrel, and the tie rod passes through the piston after entering the locking cylinder barrel; an annular groove is provided at the tail of the tie rod, and correspondingly, annular teeth are provided on the inner surfaces of the two semi-ring nuts, respectively, and the annular teeth can be inserted into the annular groove of the tie rod and bite; the semi-ring nut is also provided with a through hole, the anti-loosening gland is also provided with a through hole, and a fixing screw hole is provided on the piston, and the anti-loosening gland and the semi-ring nut are connected to the piston through screws, through holes, and fixing screw holes. The advantages of the present invention are that the tooth surface connection stress of the semi-ring nut and the tie rod is dispersed and small, and the assembly is convenient.

Description

Technical Field

[0001] The invention relates to a clamping cylinder of an injection molding machine. Background Art

[0002] The tie rod in the existing two-platen injection molding machine clamping cylinder also serves as the clamping piston rod, and the piston is directly connected to the end of the tie rod by a thread, which includes ordinary M thread, trapezoidal thread or special thread.

[0003] The existing threaded connection has the following shortcomings:

[0004] 1. The thread structure has a high stress concentration: During the normal operation of the injection molding machine, the deformation force of the tie rod in each clamping process starts from the mold contact and reaches the peak value after locking, from small to large; the mold opening process is the opposite. The tie rod cross section is subject to alternating stress, and the stress concentration coefficient at the root of the thread is high, which is prone to fatigue damage and causes early fracture of the tie rod. In order to eliminate stress concentration, it is generally necessary to increase the root fillet, etc., but due to the limitation of thread size, the improvement is limited.

[0005] 2. The thread is subjected to additional bending stress: Figure 1 As shown, when the injection molding machine is clamped, the fixed template is deformed, causing the oil cylinder installed on the template to rotate with the piston. Because there are gaps between the oil cylinder 2 and the tie rod 1, and between the piston 4 and the tie rod 1, this torque is finally transmitted to the thread engagement surface 40 of the piston and the tie rod, causing the thread to bear additional bending stress. The thread part itself bears a large pure tensile stress, plus this bending stress, the composite stress significantly increases the maximum tensile stress at the root of the thread, increasing the possibility of structural damage at the thread.

[0006] 3. The thread assembly requires high precision: for a large-mass piston, without special tooling, the tooth surface is likely to be damaged during the assembly process.

[0007] 4. The manufacturing precision of threads is high: for example, the tooth angle, pitch tolerance, and mid-diameter dimensions are difficult to process, and tiny manufacturing defects in the production process often cause early crack initiation. The quality control requirements are very high and difficult to meet. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a clamping oil cylinder with a semi-circular brake type connection, so that the stress is uniform and small, and the manufacture and installation are convenient.

[0009] The technical solution adopted by the present invention to solve the above-mentioned problems is: a locking cylinder with a semi-ring brake type connection, comprising a pull rod, a locking cylinder barrel, a locking cylinder rear cover, a piston, two half-ring nuts, and an anti-loosening pressure cover; the rear cover is fixed to the rear part of the locking cylinder barrel to form the cylinder body of the locking cylinder; the piston is placed in the inner cavity of the locking cylinder barrel, and the pull rod passes through the piston after entering the locking cylinder barrel; an annular groove is provided at the tail of the pull rod, and correspondingly, annular teeth are respectively provided on the inner surfaces of the two half-ring nuts, and the annular teeth can be inserted into the annular groove of the pull rod and engage; the half-ring nut is also provided with a through hole, and the anti-loosening pressure cover is also provided with a through hole, and a fixing screw hole is provided on the piston, and the anti-loosening pressure cover and the half-ring nut are connected to the piston by screws, through holes and fixing screw holes.

[0010] Preferably, a groove is provided at the front of the anti-loosening gland, and the rear end of the pull rod is placed in the groove, so that the anti-loosening gland can better fix the pull rod.

[0011] Preferably, the annular teeth in the inner hole of the semi-ring nut may also be triangular teeth, trapezoidal teeth, or saw-shaped teeth.

[0012] More specifically, the annular tooth of the inner hole of the semi-ring nut may be one tooth or multiple teeth, and correspondingly, the annular groove may be one or more.

[0013] Preferably, the annular groove bottom adopts a large radius transition, and it is particularly preferred that the groove bottom radius R is greater than or equal to 1 / 2 of the groove width, so that stress concentration is significantly reduced.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] 1. An annular tooth connection is set between the half ring nut and the pull rod, and the half ring nut is connected to the piston with an anti-loosening gland. The front and rear end guides of the two half ring nuts can make the tooth surfaces of the half ring nut and the pull rod not affected by the deformation of the template, but only subjected to pure tensile force, so the force is even.

[0016] 2. Compared with threads, the annular groove of the half ring nut is relatively simple to process. When assembling, you only need to buckle the half ring nut, which is very convenient to install and the surface accuracy is not affected by assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the clamping cylinder of an existing injection molding machine.

[0018] Figure 2 It is a schematic diagram of the overall structure of a clamping cylinder with a semi-circular brake type connection according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] like Figure 2As shown, a locking cylinder with a semi-ring brake type connection includes a pull rod 1, a locking cylinder barrel 2, a locking cylinder rear cover 3, a piston 4, two semi-ring nuts 5, and an anti-loosening pressure cover 6.

[0021] The tail of the pull rod 1 is provided with an annular groove 11 , and correspondingly, the inner surfaces of the two half ring nuts 5 are provided with annular teeth 51 , which are inserted into the annular groove 11 of the pull rod 1 and engaged.

[0022] The above-mentioned semi-ring nut 5 is also provided with a through hole 53, the anti-loosening cover 6 is also provided with a through hole 63, and the piston 4 is provided with a fixing screw hole 43. The anti-loosening cover 6 and the semi-ring nut 5 are connected to the piston 4 through the screw 7, the through hole 63, the through hole 53, and the fixing screw hole 43.

[0023] The rear cover 3 is fixed to the rear of the clamping cylinder barrel 2 by screws to form the cylinder body of the clamping cylinder.

[0024] The above-mentioned piston 4 is placed in the inner cavity of the cylinder barrel 2. After the pull rod 1 penetrates the cylinder barrel 2, it passes through the middle of the piston 4. The annular teeth 51 of the two half-ring nuts 5 are buckled into the annular groove 11 at the tail of the pull rod 1. Then, the two half-ring nuts 5 are fixed to the piston 4 by screws 7 and anti-loosening pressure covers 6, thereby fixing the pull rod 1 to the piston 4.

[0025] Furthermore, a groove 61 is provided at the front of the anti-loosening gland 6, and the tail end 12 of the pull rod 1 is placed in the groove 61, so that the anti-loosening gland 6 can better fix the pull rod 1.

[0026] The number of the annular teeth in this embodiment is 6, but it may also be one or another number.

[0027] The bottom of the annular groove 11 adopts a large fillet transition with a groove bottom fillet R greater than or equal to 1 / 2 of the groove width, which significantly reduces stress concentration.

[0028] When the above-mentioned locking cylinder is working, the pressure in the cylinder cavity causes the teeth connecting the half ring nut 5 and the pull rod 1 to bear axial load. The inner holes at the front and rear ends of the half ring nut and the pull rod are guided. The torque generated on the piston due to the deformation of the template is finally transmitted to the pull rod through the front and rear end guide sections of the nut, rather than being transmitted to the pull rod through the tooth surface inside the nut, so that the tooth surface is only under pure tension and the force is evenly distributed.

Claims

1. A clamping cylinder with a semi-circular brake connection, characterized in that: It includes a pull rod, a locking oil cylinder barrel, a rear cover of the locking oil cylinder, a piston, two half-ring nuts, and an anti-loosening pressure cover; the rear cover is fixed to the rear part of the locking oil cylinder barrel to form the cylinder body of the locking oil cylinder; the piston is placed in the inner cavity of the locking oil cylinder barrel, and the pull rod passes through the piston after entering the locking oil cylinder barrel; an annular groove is arranged at the tail of the pull rod, and correspondingly, annular teeth are respectively arranged on the inner surfaces of the two half-ring nuts, and the annular teeth can be inserted into the annular groove of the pull rod and bite; the half-ring nut is also provided with a through hole, and the anti-loosening pressure cover is also provided with a through hole, and a fixing screw hole is arranged on the piston, and the anti-loosening pressure cover and the half-ring nut are connected to the piston by screws, through holes and fixing screw holes, and a groove is arranged at the front of the anti-loosening pressure cover, and the tail end of the pull rod is placed in the groove.

2. The clamping cylinder with a semi-circular brake connection according to claim 1 is characterized in that: The annular teeth in the inner hole of the semi-ring nut are triangular teeth, trapezoidal teeth or saw-shaped teeth.

3. The clamping cylinder with a semi-circular brake connection according to claim 1 or 2, characterized in that: The annular teeth in the inner hole of the semi-ring nut are one tooth or multiple teeth.

4. The clamping cylinder with a semi-circular brake connection according to claim 1 or 2, characterized in that: The annular groove bottom adopts a large rounded transition.

5. The clamping cylinder with a semi-circular brake connection according to claim 4 is characterized in that: The large fillet is a groove bottom fillet R that is greater than or equal to 1 / 2 of the groove width.

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